Logical Layout of Enhanced EtherSwitch Service modules

[greywolf]

Hi,

I anybody able to explain the logical layout of the Enhanced EtherSwitch modules? Specifically what is the purpose of having two logical links to the router?

After installing the EtherSwitch Module SM-ES3G-16-P into the router, I have new interfaces Gi1/0 and Gi1/1 - these are attached to Gi0/18 and Gi0/17 respectively on the EtherSwitch (as identified through Cisco Discovery Protocol).

To connect to the EtherSwitch, I must assign an IP address to Gi1/0 and telnet using the 'service-module GigabitEthernet1/0 session' command.

I can assign sub-interfaces to Gi1/0 and establish a layer-3 connection, but what is the purpose of Gi1/1? Is it meant for layer-2?

I believe older network module versions of EtherSwitch only had one logical (GigabitEthernet x/0) interface.

I thought I might be able to establish an etherchannel using the two logical links, but interface Gi1/1 does not support the 'channel-group' command, and I get error messages when assigning the Gi0/17 and Gi0/18 interfaces to a port-channel.

If you have simple explanation that would be great, thanks.

[MHM Cisco World]

you have small site two or some more host in site, 
you need to connect this site to internet, and the host must connect to each other via L2. 
NOW 

two approach 
1- using SW for L2 host connection and using Router for connect to internet because router only support NAT (and some new SW also can support NAT)
2-using router with ether which give you the two 
SW via ether 
and Router 

this is why Ethermodule is use.

[greywolf]

Hi MHM Cisco World,

Thanks for the reply, I can certainly understand how useful the EtherSwitch Modules would be for small sites. Integrating the switching into the router is fantastic, but I was wondering why there is two logical interfaces connecting the EtherSwitch module to the router - it doesn't seem to provide any ability to increase throughput by creating an etherchannel and I'm not sure it provides redundancy given that they are logical links. I can confirm spanning tree is active on these links and will block the redundant path.

Perhaps the purpose is to provide an option for L3 config with sub-interfaces or L2 config with VLANs? I was hoping someone more knowledgeable than me could clarify.

Thanks 

[MHM Cisco World]

https://www.cisco.com/c/en/us/td/docs/routers/access/1900/software/configuration/guide/Software_Configuration/etherchannel.html

you can config Etherchannel